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| author | Björn Töpel <bjorn.topel@intel.com> | 2021-03-08 12:29:07 +0100 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2021-03-10 01:06:34 +0100 |
| commit | ee75aef23afe6e88497151c127c13ed69f41aaa2 (patch) | |
| tree | 2e6ca2aa0d6d1ac694002dd4aff11915473d4118 /kernel/bpf/cpumap.c | |
| parent | e6a4750ffe9d701c4d55212b14b615e63571d235 (diff) | |
| download | linux-ee75aef23afe6e88497151c127c13ed69f41aaa2.tar.bz2 | |
bpf, xdp: Restructure redirect actions
The XDP_REDIRECT implementations for maps and non-maps are fairly
similar, but obviously need to take different code paths depending on
if the target is using a map or not. Today, the redirect targets for
XDP either uses a map, or is based on ifindex.
Here, the map type and id are added to bpf_redirect_info, instead of
the actual map. Map type, map item/ifindex, and the map_id (if any) is
passed to xdp_do_redirect().
For ifindex-based redirect, used by the bpf_redirect() XDP BFP helper,
a special map type/id are used. Map type of UNSPEC together with map id
equal to INT_MAX has the special meaning of an ifindex based
redirect. Note that valid map ids are 1 inclusive, INT_MAX exclusive
([1,INT_MAX[).
In addition to making the code easier to follow, using explicit type
and id in bpf_redirect_info has a slight positive performance impact
by avoiding a pointer indirection for the map type lookup, and instead
use the cacheline for bpf_redirect_info.
Since the actual map is not passed via bpf_redirect_info anymore, the
map lookup is only done in the BPF helper. This means that the
bpf_clear_redirect_map() function can be removed. The actual map item
is RCU protected.
The bpf_redirect_info flags member is not used by XDP, and not
read/written any more. The map member is only written to when
required/used, and not unconditionally.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20210308112907.559576-3-bjorn.topel@gmail.com
Diffstat (limited to 'kernel/bpf/cpumap.c')
| -rw-r--r-- | kernel/bpf/cpumap.c | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c index 7352d4160b7f..0cf2791d5099 100644 --- a/kernel/bpf/cpumap.c +++ b/kernel/bpf/cpumap.c @@ -543,7 +543,6 @@ static void cpu_map_free(struct bpf_map *map) * complete. */ - bpf_clear_redirect_map(map); synchronize_rcu(); /* For cpu_map the remote CPUs can still be using the entries |